I have been using Ubuntu since 2 years, and I love it. I had never heard of it before 2011.
I currently have the 12.04 LTS version, which I would recommend since LTS (Long Term Support) versions are more stable and have updates scheduled for 5 years. Regular, non-LTS releases have updates scheduled for 9 months. Don't worry much about stability though. All Ubuntu versions are stable when released.